1982 GMC - What do I have? What can I tow?

[Dano500]

The cab is from a 8600GVW K25. Single cab, single rear wheel. Looks like someone swapped the cab onto a C30 cab and chassis frame/running gear. You can see if it is a one ton by measuring the height of the frame C-channel. I think the 3/4 ton is 5-ish inches and the 1-ton is 6-ish inches tall. I'm not sure if all cab and chassis models were 1 ton or not.

I hope it’s ok for me to ask more on this. So, what area of the frame do you measure to find out? I ask because in front of rear axle outer to outer measurement of frame is 6.5-ish, but from above rear axle to end of frame it is outside it is 4.75-ish.

 

[Autocar]

I measured where cab and bed meet, and dimension is pretty consistent forward and aft of that ahead of rear axle. And as you can see it's actually about 7.5 outside dimension.
And also didn't mention, I confirmed the rear end is 4.11.

 

[Dano500]

So, I know yours is a one ton, so I guess this confirms mine is an HD 3/4.

 

[Bextreme04]

I hope it’s ok for me to ask more on this. So, what area of the frame do you measure to find out? I ask because in front of rear axle outer to outer measurement of frame is 6.5-ish, but from above rear axle to end of frame it is 4.75-ish.

I knew that there was a 1" difference between the frames, but It appears I had my numbers wrong. 1/2 ton and 3/4 ton have the same frame height. If yours is an HD(C6P) option, the frame thickness(how thick the actual metal is) will be more than the standard 3/4 ton and all 1/2 ton frames. The picture showing his frame tells me that the frame was definitely from a 1 ton and the fact he has a 14BFF dually rear end says that it was a Cab & Chassis vehicle.

 

[Dano500]

I knew that there was a 1" difference between the frames, but It appears I had my numbers wrong. 1/2 ton and 3/4 ton have the same frame height. If yours is an HD(C6P) option, the frame thickness(how thick the actual metal is) will be more than the standard 3/4 ton and all 1/2 ton frames. The picture showing his frame tells me that the frame was definitely from a 1 ton and the fact he has a 14BFF dually rear end says that it was a Cab & Chassis vehicle.

So, it’s not the height of the C channel, but the thickness of the metal that determines if I have the HD, or LD 3/4 ton truck. I will search for frame thickness numbers, unless anyone here knows where I can find that info. Much appreciated.

 

[Bextreme04]

So, it’s not the height of the C channel, but the thickness of the metal that determines if I have the HD, or LD 3/4 ton truck. I will search for frame thickness numbers, unless anyone here knows where I can find that info. Much appreciated.

https://www.gmsquarebody.com/threads/revisiting-k10-vs-k20-vs-k30-frame-specs.11279/

 

[Dano500]

@Bextreme04 you rock, thanks a bunch.